1. Technical Field
The present invention relates to a photoelectric converter device and a method for its manufacture.
2. Related Art
In an electric power generation system using solar light, a photoelectric conversion panel formed by laminating an amorphous, microcrystalline, or other semiconductor thin film is used. When such a photoelectric conversion panel is applied to a solar power generation system, the panel is installed as a photoelectric converter device (module) having a module frame member attached to the outer periphery thereof.
FIGS. 12 to 14 show example structures generally used for a photoelectric converter device (module). FIG. 12 shows a super straight structure used for a thin-film solar cell such as a thin-film silicon solar cell, and FIG. 13 shows a super straight structure used for a monocrystalline or polycrystalline silicon solar cell. In these structures, a photoelectric conversion panel 100 is sealed by a glass plate (glass substrate) 10 and a sealant 12, and, on the sealant 12 side, a back sheet 14 having a metal thin film or the like for preventing ingress of moisture and the like during outdoor use is further overlapped. In addition, on the outer periphery of the photoelectric conversion panel 100, an end face seal 16 is provided for preventing ingress of moisture and the like from the end faces and for preventing breakage, and a module frame member 18 is provided further on the outside for reinforcement.
FIG. 14 shows an example of a glass package structure. In this structure, the above-described back sheet 14 is replaced with a glass plate 20. Further, at each of the end faces of the photoelectric conversion panel 100, an end face seal 22 is filled between the glass plate 10 on the front surface side and the glass plate 20 on the back surface side so as to prevent ingress of moisture and the like.
Meanwhile, U.S. Pat. No. 5,656,186 discloses a technique of welding glass components to each other by radiating a laser beam having a pulse width of the order of femtoseconds.
In the case of a super straight structure, when outdoor use is continued over a long period of time, there are risks that moisture and the like may penetrate and ingress through the back sheet 14 and the sealant 12. Further, ingress of moisture and the like from the end faces may cause failures such as output degradation and line disconnection. Changes in outer appearance may also result due to peeling of films and the like. If long-term reliability of this structure is to be improved, enhancements must be made in the characteristics of the sealing members, and the amount of use of the sealing members must also be increased, leading to higher costs.
In the case of a glass package structure, as it is very difficult to prevent ingress of moisture and the like from the end faces, a special end face seal must be employed, such that increased costs are required. Further, in the case of a structure that does not use the module frame member 18, as the sealant 12 softens under high temperatures during the summer season, there are risks that the relative positions of the glass plate 10 and the glass plate 20 may become shifted.
On the back surface side of the photoelectric conversion element formed on the front surface glass plate 10, there are arranged components such as collector wiring lines for collecting and extracting electric power to the outside of the photoelectric converter device, and also insulating sheathing material for insulating between the collector wiring lines and the back surface electrode of the photoelectric conversion element. Accordingly, a gap is created between the front surface glass plate 10 and the back surface glass plate 20. When air remains inside this gap, expansion and contraction of the air occur due to solar radiation and the like, such that risks of breakage of the glass plates 10, 20 and water ingress via the gap arise.
Meanwhile, if the glass plate 10 and the glass plate 20 are fixed to each other while applying pressure so as to minimize the gap, stress would be applied to the glass plate 20 due to the convexity of the back-surface structures of the photoelectric conversion element, possibly causing breakage.